The present disclosure, in some embodiments thereof, relates to material dispensing and, more particularly, but not exclusively, to laser-induced material dispensing.
Many technologies are enabled, facilitated or improved by the ability to pattern a wide variety of materials for specific purposes. Examples of patterning techniques that may be used for defining patterns in materials or depositing materials in desired patterns include contact lithography, projection lithography, screen printing, inkjet printing, and a variety of direct write technologies.
Direct write technologies are considered advantageous in that they allow the materials to be deposited, and patterns defined therein, quickly without the intermediate step of producing a mask, as is typically required for traditional lithography processes. Several direct write technologies are known. These include inkjet printing, laser chemical vapor deposition (LCVD), laser engineered nano-shaping (LENS), and laser induced forward transfer (LIFT).
In LIFT, a pulsed laser beam is directed through a laser-transparent target substrate to strike a film of material coated on the opposite side of the target substrate. The laser vaporizes the film material as it absorbs the laser radiation and, due to the transfer of momentum, the material is removed from the target substrate and is redeposited on a receiving substrate that is placed in proximity to the target substrate.
Laser induced forward transfer is typically used to transfer opaque thin films, typically metals, from a pre-coated laser transparent support, to the receiving substrate. Various apparatus employing laser-induced forward transfer are known. For example, U.S. Published Application No. 20140160452 discloses an apparatus in which the donor is refreshed to enable continued material deposition. The refreshment can be substitution of a new donor structure for a donor structure used during exposure, regeneration of the donor material on the donor structure, use of a flexible membrane that is rolled, or use of a conveyor system to transport fresh donor structure to the deposition area.
Further, conventional LIFT systems are slow, expensive, and are generally only capable of depositing a single material on a receiver substrate.
Usually the “LIFT system” approach and its requirement of long term robustness has led all innovators to optimize for continuous delivery using permanent parts only. This constraint increases the complexity of the system and reduces flexibility in term of the ability to deliver multi-material, material mixing and variable coating thickness.
Furthermore, for example, in conventional LIFT systems the laser is large and forms part of the print head; and therefore, the print head cannot be made compact (i.e., since the laser is integrated into the print head.) Further, the wait time between successively depositing droplets of a donor material on a substrate and the linear movement of the scanner makes the conventional LIFT print head slow. Therefore, in order to have the conventional LIFT system operate at a reasonable rate, very expensive optics must be provided for the conventional LIFT system.
Also, the conventional LIFT system has a disadvantage in that when it deposits two droplets next to each other, it needs to wait a few milliseconds in between droplets. During this time, no printing can take place, to avoid material disturbance. This wait time or “relaxation time” is disadvantageous because it reduces the throughput of the LIFT system.
Additional background art includes U.S. Pat. Nos. 4,752,455, 4,895,735, 5,725,706, 5,292,559, 5,492,861, 5,725,914, 5,736,464, 4,970,196 and 5,173,441.